One scaling technique for improving the density of a semiconductor device is the use of a multi-gate transistor in which a semiconductor fin is formed on a substrate and a gate is formed on a surface of the semiconductor fin. Since such a multi-gate transistor uses a three-dimensional channel, it is easy to perform scaling. Moreover, even if a gate length of the multi-gate transistor is not increased, the current control capability may be improved. Additionally, it is also possible to effectively suppress a short channel effect (SCE) in which the potential of the channel area is influenced by a drain voltage.